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Commit 0ac27779 authored by Hendrik Brueckner's avatar Hendrik Brueckner Committed by Martin Schwidefsky
Browse files

s390/fpu: add static FPU save area for init_task 



Previously, the init task did not have an allocated FPU save area and
saving an FPU state was not possible.  Now if the vector extension is
always enabled, provide a static FPU save area to save FPU states of
vector instructions that can be executed quite early.

Signed-off-by: default avatarHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent b5510d9b

arch/s390/include/asm/processor.h

+2 −0
Original line number Diff line number Diff line
@@ -139,8 +139,10 @@ struct stack_frame { 


#define ARCH_MIN_TASKALIGN	8



extern __vector128 init_task_fpu_regs[__NUM_VXRS];

#define INIT_THREAD {							\

	.ksp = sizeof(init_stack) + (unsigned long) &init_stack,	\

	.fpu.regs = (void *)&init_task_fpu_regs,			\

}



/*

arch/s390/kernel/entry.S

+0 −4
Original line number Diff line number Diff line
@@ -762,8 +762,6 @@ ENTRY(save_fpu_regs) 
	stfpc	__THREAD_FPU_fpc(%r2)

.Lsave_fpu_regs_fpc_end:

	lg	%r3,__THREAD_FPU_regs(%r2)

	ltgr	%r3,%r3

	jz	.Lsave_fpu_regs_done	  # no save area -> set CIF_FPU

	tm	__LC_MACHINE_FLAGS+5,4	  # MACHINE_HAS_VX

	jz	.Lsave_fpu_regs_fp	  # no -> store FP regs

.Lsave_fpu_regs_vx_low:
@@ -1193,8 +1191,6 @@ cleanup_critical: 
	stfpc	__THREAD_FPU_fpc(%r2)

1:	# Load register save area and check if VX is active

	lg	%r3,__THREAD_FPU_regs(%r2)

	ltgr	%r3,%r3

	jz	5f			  # no save area -> set CIF_FPU

	tm	__LC_MACHINE_FLAGS+5,4	  # MACHINE_HAS_VX

	jz	4f			  # no VX -> store FP regs

2:	# Store vector registers (V0-V15)

arch/s390/kernel/process.c

+4 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <linux/kprobes.h>

#include <linux/random.h>

#include <linux/module.h>

#include <linux/init_task.h>

#include <asm/io.h>

#include <asm/processor.h>

#include <asm/vtimer.h>
@@ -36,6 +37,9 @@ 


asmlinkage void ret_from_fork(void) asm ("ret_from_fork");



/* FPU save area for the init task */

__vector128 init_task_fpu_regs[__NUM_VXRS] __init_task_data;



/*

 * Return saved PC of a blocked thread. used in kernel/sched.

 * resume in entry.S does not create a new stack frame, it